WITH the open-water season now underway, endurance swimmers are gearing up to test their limits once more – facing icy swells, strong currents and unpredictable weather.
As they take on South Africa’s toughest stretches, from Dassen Island to False Bay, Rooibos is emerging as an unlikely performance ally. Long seen as a comfort drink, research suggests its unique antioxidant makeup can help manage oxidative stress, enhance hydration and aid recovery.
For decades, the caffeine-free brew has quietly powered swimmers across some of the world’s most treacherous stretches – from Robben Island to the English Channel – earning its reputation as a trusted hydration partner among endurance athletes.
According to Tracey Steyn, Chairperson of the Cape Long Distance Swimming Association (CLDSA), drinking Rooibos with honey or maple syrup – sometimes mixed with maltodextrin (a source of rapidly absorbed carbohydrates) has become an integral part of the country’s open-water swimming culture.
She says Rooibos can be found on most support boats and is regarded as a standard element of feeding protocols.
“While it’s especially popular among South African marathon swimmers, it’s also used by a number of international athletes. The practice is not exclusive to South Africa, yet it’s become a well-established and distinctive part of our open-water swimming culture,” remarks Steyn.
Though no one knows exactly when Rooibos became the drink of choice for endurance swimmers, Steyn explains that the tradition evolved organically.
“Rooibos provides sustained hydration and is gentle on the stomach. It’s advice that’s been passed down by coaches, boat skippers and seasoned swimmers over many years. When combined with a little honey, it also helps counteract the salty taste from hours in seawater.
Being naturally caffeine-free, it doesn’t contribute to a drop in body temperature and, when served warm, helps maintain body warmth and energy levels – making it ideal for icy swims like the Robben Island Crossing or False Bay challenges, where water temperatures can drop to between 11°C and 15°C, depending on the season and currents.
“Traditional sports drinks can sometimes cause nausea or become overly sweet after prolonged use,” says Steyn. “Rooibos, by contrast, is light, hydrating and easy to tolerate over long durations, making it a preferred choice for endurance swimmers.”
Swimmers typically sip Rooibos every 30 to 45 minutes during a long swim. It’s usually brewed strong, served warm in small bottles and sometimes mixed with electrolytes, honey or a pinch of salt. Many also drink it before a swim to pre-hydrate and after finishing to aid recovery.
She says what began as a distinctly local custom has spread to international waters as many visiting swimmers who compete in South African events adopt the Rooibos habit, including some of the sport’s biggest names.
“Several prominent international swimmers have incorporated Rooibos into their nutrition strategies – among them Alison Streeter, known as the ‘Queen of the Channel’, who famously included Rooibos in her feeding programme,” notes Steyn.
The tisane’s gentle yet effective properties have even caught the attention of international endurance athletes in other disciplines – from ultra-runners to mountain climbers – who value its natural benefits.
The anecdotal evidence from the open-water community is also supported by science. Prof Simeon Davies, Head of the Sports Department at the Cape Peninsula University of Technology (CPUT), has led several studies into Rooibos’ potential performance-enhancing effects for athletes.
His research has shown that Rooibos contains polyphenols and flavonoids, powerful antioxidants that reduce inflammation, oxidative stress and muscle damage – all of which affect endurance and recovery.
“Rooibos is still an underappreciated beverage in sports considering its health benefits,” says Prof Davies. “It contains bioactive compounds that could decrease oxidative stress, inflammation, muscular damage, fatigue and soreness – all factors that impact athletic performance.”
In controlled exercise trials, athletes who drank Rooibos before and during exertion showed signs of reduced fatigue and improved endurance by up to 5%, a crucial edge in competitive sports. Further research into submaximal exercise, the foundation of most athletic training, also showed that including Rooibos as part of pre- and mid-session hydration led to significant improvements in endurance performance.
Prof Davies adds that Rooibos is an excellent hydration aid.
“Even a slight drop in hydration can affect performance, but many athletes struggle to drink enough plain water. Rooibos ticks all the boxes – it hydrates effectively, tastes great and doesn’t contain caffeine or sugar, which can lead to crashes,” he says.
His team also led a pilot study investigating Rooibos’ potential to curb altitude sickness during a climbing expedition on Aconcagua, Argentina’s 6 962m peak. Findings suggest that the tisane’s antioxidant compounds may protect against oxidative stress linked to high-altitude conditions – opening new doors for research into Rooibos’ role in sports and recovery.
The health benefits of Rooibos were reinforced by a recent systematic literature review, in which Prof Kathryn Speer of the University of Canberra and colleagues outlined its potential positive effects in humans, particularly in relation to measures of cardiometabolic health.
When it comes to Rooibos and exercise performance, pioneering research by Dr Oiva Viety Kamati at CPUT’s Applied Microbial and Health Biotechnology Institute (AMHBI) – using advanced analytical techniques, such as metabolomics and examining exercise genotype–phenotype relationships – supports anecdotal reports from endurance swimmers.
Dr Kamati found that Rooibos boosted the body’s natural antioxidant defences, aiding faster recovery. The study also showed that Rooibos positively influenced metabolic responses during submaximal exercise, underscoring its potential as a natural ergogenic aid.
Both Prof Davies and Prof Marnewick, who have guided Rooibos research at CPUT in collaboration with national and international universities, agree that its use among endurance swimmers is scientifically sound and may enhance both performance and recovery.
Steyn agrees that scientific studies could help validate what swimmers have long known.
“With growing scientific evidence confirming the benefits of Rooibos for hydration, recovery and overall health, it’s exciting to see research catching up with what the open-water community has practised for years,” she says.
“While there’s still limited data specific to marathon swimming, Rooibos remains a valuable area for ongoing investigation – particularly in how its antioxidant content, thermoregulatory properties and gut-friendly nature support endurance performance.
The CLDSA would welcome more studies that build on these findings and further substantiate the long-standing use of Rooibos in open-water swimming.”
With the South African open-water season running from October through May, swimmers are once again gearing up for the country’s signature challenges – with bottles of Rooibos ready to go.
For many, it’s not just about tradition or taste, but trust. “Rooibos isn’t just a ritual,” says Steyn. “It’s simply what works – practical, proven and proudly South African.”
Image supplied (Endurance swimmers pause for a sip of warm Rooibos during an open-water swim. The caffeine-free brew has long been part of South Africa’s ocean swimming tradition).
